Enzyme‐Like Catalytic Activity of Porphyrin‐Functionalized Ceria Nanotubes for Water Oxidation

Abstract

Artificial enzymes have broad applications in catalysis and can be used to help understand catalytic mechanisms. Nanoceria has various enzyme‐mimetic properties that depend on the relative content of Ce3+ and Ce4+. In this context, CeO2 nanotubes was investigated as catalase mimics for water oxidation. The photosensitizer 5,10,15,20‐meso‐tetra(4‐carboxyphenyl) porphyrin (TCPP) was facilely embedded in CeO2 nanotubes (TCPP@CeO2 NTs), and photoinduced charge transfer was shown to occur between the strongly coupled TCPP and CeO2, which leads to effective charge separation and charge redistribution within the hybrids. As a consequence, formation of H2O2, a competing process in water oxidation and a key factor that affects the oxidative stability of photoelectrodes, was effectively inhibited on TCPP@CeO2 NTs. These findings show that enzyme mimics can be used for the selective generation of reactive oxygen species, and therefore to control the kinetics of water oxidation.

Spin-control in electrocatalysis for clean energy

“…Moreover, the chiral molecule coating also prevented the production of H2O2 in neutral and acidic conditions that favor the reaction pathway towards H2O2 (Figure 3b). This study inspired several other attempts [34,35,36] to use the CISS effect to boost the OER, including using catalysts consisting of layered transition metal chalcogenides [37] . Recently, Pan et al demonstrated that tuning the electron spin polarization in titanium dioxide by changing the density of metal vacancies can improve its photocatalytic activity [38] .…”

Spin‐Control in Electrocatalysis for Clean Energy

“…Moreover, the chiral molecule coating also prevented the production of H 2 O 2 in neutral and acidic conditions that favor the reaction pathway towards H 2 O 2 (Figure 3b). This study inspired several other attempts [34,35,36] to use the CISS effect to boost the OER, including using catalysts consisting of layered transition metal chalcogenides [37] . Recently, Pan et al.…”

Nanostructured Ceria: Biomolecular Templates and (Bio)applications

“…The ability of nanosized ceria to promote the formation of radical oxygen species has been exploited in photocatalytic water oxidation, too [ 15 , 108 ]. For instance, a porphyrin photosensitizer was embedded in ceria nanotubes so that the electronic communication between the two components allowed for the enhanced production of molecular oxygen over the competing hydrogen peroxide generation from the partial water oxidation [ 109 ]. Nanosized ceria was also reported to enhance the performance of microbial fuel cells by creating oxygen reservoirs for the oxygen reduction reaction (ORR), while direct involvement of the cerium redox couple in the catalysis was only marginal [ 110 ].…”